Method of making tractor-wheel lugs



.33, 1929. H. E. Msc-RAY Hamon o? MAKING TRAcToR WHEEL Lues Filed April 23, 1927 Patented `luly 23, 1929.

UNITED STATES HAROLD E. MCCR-AY, OF WATERLOO, IOWA,

ASSIGNOR TO JOHN DEERE TRACTOR COM- PANY, OF WATERLOO, IOWA, A CORPORATION OF IOWA.

METHOD OF MAKING TRalCTOR-WHEEL LUGS.

Application niednprn 23,

The present invention relates to tractor wheel lugs, and pertains more specifically to the manufacture of tractor lugs of the so called spade type which are characterized by a base portion for attaching to the wheel, an upstanding tip or traction portion for engaging with the ground, and lateral side walls 'extending between the base and traction portions at the sides of the lug.

@ne of the objects of the invention is to provide an improved and simplified method of manufacturing these lugs, based principally upon the use of a blank of a particular shape. As will hereinafter appeal', by the use of a blank of this shape, the manufacturing cost of the lug is greatly reduced, both from the standpoint of operations neeessary to be performed thereon, and material saved.

Another object of the invention is to provide, as the product of this method, an improved construction of tractor lug characterized by side webs of increased sectional thickness, and by a pointed or wedge-shaped formation, which is particularly desirable.

Referring to the accompanying drawing illustrating the manner of carrying out my invention Figure l is a fragmentary side view of a tractor wheel, showing lugs of the present type mounted thereon.

Fig. 2 is a detail sectional view illustrating the manner of attaching these lugs to the wheel.

Fig. 3 is a perspective view of one of the completed lugs.

Fig. 4 is a transverse sectional view taken approximately on the plane of the line eL--l of Fig. 3.

Fig. is an end elevational view of one of the lugs, and

Fig. 6 is a view illustrating the form of the blank from which the lug is produced.

Tractor lugs of the so-called spade type are characterized by a base portion or attaching flange l0, a tip or traction portion l1, which projects outwardly at an angle to the base portion for engaging the ground, and side webs 12 which extend between the side edges of the base and tract-ion portions. The base portion l0 is usually provided with a square or polygonal hole 18 punched therein for receiving the correspondingly formed shank of an attaching bolt 14 by which the lug is bolted to the tire of the tractor Wheel.

1927. Serial No. 185,929.

The polygonal shank portion of the bolt is adapted to extend into a correspondingly formed hole in the wheel for preventing the lug from turning on the tire of the Wheel. ln making these lugs, the blanks therefor are first punched from flat metal stock, preferably steel. Fig. 6 illustrates these blanks as being punched from bar or strip stock of approximately the same width as the blank', which I find to be the most economical practice. Particular attention is directed to the elongated or oval form of the blank, which, as l hereinafter describe, is an important factor' as it enables me to simplify the manufacture of the lug and to produce a lug of improved construction. These blanks are heated and are then subjected to a forging operationby which in a single stroke of the forging dies the two end portions of the blank are folded at an angle to each other to form the base flange l() and traction iange 1l, and by which the side portions are folded inwardly to form the lateral reinforcing .webs l2 extending across the sides of the lug. There is no need of describing the specific forms of the dies to be used in the performance of this forging or punching operation, as such will be evident from the shape of the finished lug. lVhile it is practicable to form the lug in a single forging or punching operation, it will of course Y be. understood that if desired the shaping may be extended over two forging operations with a heating step in between. The

punching of the hole 13 is preferably per` formed as a separate operation.

Referring now to the specific form of the original blank, and to the advantages accruing to this form, it will be seen that the blank is approximately oval or egg shaped in outline. lhile I have found that the general outline shown in Fi g. 6 is preferable, it will of course be understood that the exact proportions may be varied somewhat, the important consideration being that the blank is longer in the plane of the base and traction flanges than in the plane eX- tending transversely of the lug. The preeminent advantage obtained by punching the blanks of this formation is that the finished lug has a relatively sharp wedge-shaped formation, as best shown in Figs. l and 2.

The lug has this sharp wedge-shaped profile when it is removed from the forging dies, thus avoiding the necessity of any trimming operation to obtain that result. vWhere the blank lis broad as 'it is long i. e. substantially circular, the side portion of the blank projects outwardly to an objectionable degree from the open side of the lug, forming lateral webs of approximately the shape indicated in dotted lines in Fig. 2. This results in a lug of very blunt shape which will not be capable of penetrating hard soils nearly as well as the more v'sharply pointed 'lug which I obtain. To secure the more desirable wedge shaped formation, a lug so constructed requires subsequent trimming operations to cut the side webs down to the desired width. Two of such trimming operations must be performed, one on each side web, and these are asource of additional expense and result' in a waste of material.

These disadvantages are lavoided when using a blank of the general form illustrated in Fig. 6. The greater length of such blank results in an increased height of thetraction flange 11, andthe reduced width of the blank results in relativelynarrow side webs, the free or marginal edges of which lie inside of a straight line extended between the end of the baseflange and the end of the traction flange. T he vfinished lug is therefore of Irelatively Vsharp wedge-shaped formation, and is vproduced by a single stroke ofthe forging'dies, Athus dispensing with 'any subsequent trimming operation. By virtue of the form,` of the blank such formation can be obtained by the use of straight dies.V 5Furthermore, by lI'naking the blanks of elongated form it is possible to use stock of narrower width, which effects a further saving of `material. The relatively obtuse curve v at that end ofthe blank which forms the traction flange also results in the tip edge of such flange having a greater wearing area Vforcontacting with the ground.

vIn the forging of a bla-nk of this oval 0r elongated outline the metal in the side portions of the blank is crowded inwardly so that the edges of the side webs adjacent-to the tip end of the lug extend outwardly along the comparatively straight lines indicated at 16, and the edges of these side webs adjacentto the base portion of the flange curve forwardly to the end of such base portion, as indicated at 17, leaving a pronounced dip in the edges of the webs. This gives a relatively slender taper to the tip "portion vof the lug, while leaving ample reinforcing metal 'adjacent to the base portion of the lug. The crowding of the metal adjacentto the inwardly dipped edges of the webs also results in such portions of the webs being'thickened beyond the sectional thickness of'the `stock. This is best shown at 18-in Figs. 4 and 5, the dotted lines in Fig. 4 represeiiting the thickness of the 'originalstock and the inwardly curved portions 18 representing the additional thickness resulting vfrom the Icrowding of the metal in `the intermediate areas of the side webs. These thickened side walls add reinforcement to the tip portion of the lug against the bending and fracturing stresses set up in the lug in its engagement with the ground.

lVhile I have described this lug as being intended primarily for use on tractor wheels, it will be evident that it may also be used on the wheels of farm implements and vehi- 'cles generally where ellicient Atractive engagement with the groundis desired.

lfVhat l claim as 'inyinvention and desire to secure by Letters Patent, is-

1. The method of making a wheel lug of the class described, consisting in vpunching out a. blank of substantially oval shape and of a mass equal `to the total mass of the lug to be formed, and then forging the lug `from the blank with the broader portion of V1'che blank forming the base of the lug and the narrower portionof the blank forming the traction portion of the lug, the lateral portions ofthe blankforming lateral webs connecting the base and traction protions.

2. The method of making a wheel lug of the class described, consisting in Vproviding 'a blank'tapering toward one end and of a' mass equal to the Amass of the lugto be formed, and then forging the lug from the blank with the broader portion ofthe blank forming the base of the lug and the narrower portion of the blank forming the traction portion of the lug, the lateral portions of the blank forming lateral webs connecting the base and traction portions, the metal of said lateral portions of the yblank being crowded inwardlyduring the forging operation thereby imparting increased vthickness to the web elements for reinforcing the same. n 3. The method of making a wheel lug' of the class described, comprising a base portion, a tractionportion in yangular relation to the base portion, and a web element connecting said portions, which consists in forming a blank from stock having a thickness substantially equal to the thickness of the traction portion of the lug to be formed, and then forging the lug from the blank, the excess metal ofthe web element vdue to the bending of said base and traction portions into angular relation to eachother being crowded inwardly during the forging operation to impart increased'thickness to such webelement Vfor reinforcing the same.

4L. 'The method of making a wheel lug of the class described. comprising a ybase portion, a tract-ion portion disposed in angular relation to the baseportion and of susbtan tially uniform'thickness, and web elements connecting the base-and the traction portions, which consists inforging the lugV from a nfiat llO blank having a thickness substantially equal to the thickness of the traction portion, the excess metal of the web elements due to the bending' or' the traction and the base portions into angular' relation to each other being crowded inwardly of said elements during the forging operation thereby imparting increased thickness to the web elements for reinforcing the same.

5. The method of making a wheel lug of the class described, comprising a base portion, a traction portion in angular relation to the base portion, the base portion and the traction portion being of substantially uniform thickness, and web elements connecting said portions, which consists in providing a blank tapering toward one end and of uniform thickness, the blank approximately corresponding in thickness to the thickness of the base and traction portions of the lug, and then forging the lug from the blank, the excess metal of the web elements due to the bending of said base and traction portions into angular relation to each other being crowded inwardly during the forging operation to impart increased thickness to such web elements for reinforcing the same.

HAROLD E. MGCRAY. 

